Technical Field
This invention relates to closures or stoppers for containers containing liquids, low viscosity substrates, and small solids, and more particularly, to closures or stoppers having a substantially cylindrical shape and comprising substantially flat terminating surfaces forming the opposed ends of said closure and employable as a stopper for a container.
More particularly, this invention relates to closures and stoppers comprising decorative indicia such as letters, symbols, colors, graphics, and wood tones printed on at least one of the substantially flat terminating surfaces forming the opposed ends of said closure or stopper.
Furthermore, this invention relates to a method of applying indicia on at least one of the two substantially flat terminating surfaces forming the opposed ends of a closure for a product retaining container, said closure having a substantially cylindrical shape and being constructed for being inserted and securely retained in a portal forming neck of the container.
Background Art
In view of the wide variety of products that are sold for being dispensed from containers, particularly containers with round necks which define the dispensing portal, numerous constructions have evolved for container stoppers or closure means for the portals. Generally, products such as vinegar, vegetable oils, laboratory liquids, detergents, honey, condiments, spices, alcoholic beverages, and the like, impose similar requirements on the type and construction of the closure means used for containers for these products. However, wine sold in bottles represents the most demanding product for bottle closure means, due to the numerous and burdensome requirements placed upon the closure means used for wine bottles. In view of these demands, most wine bottle closures or stoppers have been produced from a natural material known as “cork”.
While natural cork still remains the dominant material for wine closures, synthetic wine closures have become increasingly popular over the last years, largely due to the problem of wine spoilage as a result of “cork taint”, a phenomenon that is almost exclusively associated with natural cork materials. Known synthetic closures generally comprise a foamed plastic material having a closed cell structure and are made, for example, by extrusion, in particular co-extrusion, or injection molding. Wine closures made from natural cork or synthetic materials are the preferred bottle closure for wine storage, particularly for medium and high quality wines where tradition, the wine mystique and the bottle opening ritual with a corkscrew, are a very important, though intangible, aspect of the wine consumption.
Closures for wine bottles must satisfy very stringent requirements. In particular, one of the principal difficulties to which any bottle closure is subjected in the wine industry is the manner in which the closure is inserted into the bottle. Typically, the closure is placed in a jaw clamping member positioned above the bottle portal. The clamping member incorporates a plurality of separate and independent jaw members which peripherally surround the closure member and are movable relative to each other to compress the closure member to a diameter substantially less than its original diameter. Once the closure member has been fully compressed, a plunger moves the closure means from the jaws directly into the neck of the bottle, where the closure member is capable of expanding into engagement with the interior diameter of the bottle neck and portal, thereby sealing the bottle and the contents thereof.
In view of the fact that the jaw members must be independent of each other and separately movable in order to enable the closure member to be compressed to the substantially reduced diameter, each jaw member comprises a sharp edge which is brought into direct engagement with the closure member when the closure member is fully compressed. Depending upon the composition of the closure member, score lines are frequently formed on the outer surface of the closure member, which prevents a complete, leak-free seal from being created when the closure member expands into engagement with the bottle neck.
Thus, any synthetic bottle closure must be able to withstand this conventional bottling and sealing method. Furthermore, many cork sealing members also incur damage during the bottling process, resulting in leakage or tainted wine.
Another problem inherent in the wine industry is the requirement that the wine stopper must be capable of withstanding a substantial pressure build up that occurs during the storage of the wine product after it has been bottled and sealed. Due to natural expansion of the wine during hotter months, pressure builds up, imposing a burden upon the bottle stopper that must be resisted without allowing the stopper to be displaced from the bottle. As a result, the bottle stopper employed for wine products must be capable of secure, intimate, frictional engagement with the bottle neck in order to resist any such pressure build up.
A further problem inherent in the wine industry is the requirement that secure, sealed engagement of the stopper with the neck of the bottle must be achieved virtually immediately after the stopper is inserted into the neck of the bottle. During normal wine processing, the stopper is compressed, as detailed above, and inserted into the neck of the bottle to enable the stopper to expand in place and seal the bottle. However, such expansion must occur immediately upon insertion into the bottle since many processors tip the bottle onto its side or neck down after the stopper is inserted into the bottle neck, allowing the bottle to remain stored in this position for extended periods of time. If the stopper is unable to rapidly expand into secure, intimate, frictional contact and engagement with the walls of the neck of the bottle, wine leakage will occur.
A further requirement imposed upon closures or stoppers for wine bottles is the requirement that the closure be removable from the bottle using a reasonable extraction force. Although actual extraction forces extend over a wide range, the generally accepted, conventional extraction force is typically below 100 pounds.
In achieving a commercially viable stopper or closure, a careful balance must be made between secure sealing and providing a reasonable extraction force for removal of the closure from the bottle. Since the requirements for these two characteristics are in direct opposition to each other, a careful balance must be achieved so that the stopper or closure is capable of securely sealing the wine in the bottle, preventing both leakage and gas transmission, while also being removable from the bottle without requiring an excessive extraction force.
Another requirement for commercially viable wine stoppers or closures is a low oxygen permeability. Too much oxygen can cause the premature spoilage of wine. In fact, oxidation occurs over a period of time to render the beverage undrinkable. Thus, it is necessary to effectively prevent oxygen from entering the bottle in order to extend and preserve the freshness and shelf life of the product. Any commercially viable wine stopper or closure should therefore have a low oxygen transfer rate (OTR). It was found that the oxygen transfer rate is closely associated with the homogeneity of the cell structure of the closure and the outer surface of the substantially flat terminating surfaces forming the opposed ends of said closure.
Finally, it is desirable to provide decorative indicia such as letters and ornaments on the surface of wine stoppers (e.g. the crest or emblem of a winery). Natural corks are generally marked by a method commonly referred to as “fire branding”, i.e. by the application of a hot branding tool. Alternatively, natural corks may also be branded by application of colors or dyes. Due to food safety concerns, marking of natural corks with colors or dyes is generally only effected on the curved cylindrical surface of the cork that is not in direct contact with the wine. On the other hand, marking on the flat terminating surfaces of natural corks is generally effected by means of fire branding only since this method does not impose any food safety concerns.
It is also known to brand synthetic closures. Synthetic closures are commonly branded by means of inkjet printing using special dyes or colors approved for indirect food contact. Since such colors and dyes are normally not approved for direct food contact marking of synthetic closures with colors or dyes is generally only effected on the curved cylindrical surface of the cork that is not in direct contact with the wine. Therefore, marking on the flat terminating surfaces of synthetic closures is generally only known for injection molded closures, where marking is affected during the molding process of the closure by providing raised portions on the flat terminating surfaces.
In contrast thereto, there is currently no method available for marking the flat terminating surface of synthetic closures that have been manufactured by means of extrusion, in particular by co-extrusion. Although laser marking may, in theory, be a feasible method since it allows the avoidance of direct food contact, this method is inherently slow and expensive since it requires the use of special laser dye additives. Also, there have been concerns that laser marking of the flat terminating surfaces of synthetic closures may adversely change the foam structure of the core element, which may, in consequence, adversely affect the sensitive gas permeation properties of such closures.
Therefore, the present disclosure provides a method of applying indicia on at least one of the two substantially flat terminating surfaces forming the opposed ends of a closure for a product retaining container that does not give rise to any food safety concerns, is economically feasible, and/or does not have a significant effect on gas permeation or mechanical properties of the closure.